Allow postPersist be invoked immediately after persist()

Details

Description

OpenJPA invokes postPersist call back after commit or flush. This is compliant to JPA spec. But the spec itself is slightly ambiguous about what a 'persistent identity' is and when it is assigned to a persistent instance.
But if an application wants to receive a postPersist callback immediately after persist() – currently there is no choice.

This is a proposal to allow a configuration option for such behavior. A boolean option (added to MetaDataDefaults) that controls whether postPersist() is called back after commit/flush (default behavior as it exists now) or immediately after persist().

Given that the proposed configurable behavior is beyond the spec, I will welcome your comments/views.